Method as well as test system for testing a device under test

ABSTRACT

The present disclosure relates to a method for testing a device under test by using a test system. The method comprises the steps of: generating a wideband modulated signal; forwarding the wideband modulated signal to an input of a device under test; separating an electromagnetic wave reflected at the input by the directional element; forwarding the reflected electromagnetic wave to a test and measurement instrument; processing a reference signal associated with the wideband modulated signal; and determining a channel response by taking the reference signal and at least one scattering parameter of the device under test into account, wherein the scattering parameter depends on the reflected electromagnetic wave. Further, the present disclosure relates to a test system.

FIELD OF THE DISCLOSURE

Embodiments of the present disclosure relate generally to a method fortesting a device under test by using a test system. Further, embodimentsof the present disclosure relate generally to a test system for testinga device under test.

BACKGROUND

Nowadays, many electronic devices that process electromagnetic signalshave to be tested with regard to different characteristics. Accordingly,at least two different test stations are required to perform thesedifferent tests. For instance, a first test station comprises a vectornetwork analyzer (VNA) that is used to measure a port matching of therespective device, namely measuring the respective port matchingparameters of the device under test. The port matching measurement istypically done by means of an approach based on a continuous wave (CW)signal. Moreover, a second test station may be used to test therespective device, which comprises a signal generator, e.g. a vectorsignal generator (VSG), and a test and measurement instrument, e.g. avector signal analyzer (VSA). The VSG and VSA are used to measurecertain parameters requiring a modulated stimulus. The respectiveparameters obtained by means of the second test station may be used fordetermining an adjacent channel leakage power ratio (ACLR) or an errorvector magnitude (EVM). Generally, ACLR defines the ratio of transmittedpower on an assigned channel to power received in an adjacent channel.EVM is a measure to quantify the performance of the electronic device tobe tested, particularly a receiver or a transmitter.

However, the respective tests take long, as a continuous wave signal isused for testing the port matching, resulting in a respective frequencysweep of the test signal. In addition, the device under test has to beplaced into two different test stations subsequently, which in turnresults in higher costs due to the different test stations and moreefforts.

SUMMARY

Accordingly, there is a need for a cost-efficient and fast way to test adevice under test.

Embodiments of the present disclosure provide a method for testing adevice under test by using a test system. The method comprises the stepsof:

-   generating a wideband modulated signal by means of at least one    signal generator,-   forwarding the wideband modulated signal to an input of the device    under test via at least one directional element,-   separating an electromagnetic wave reflected at the input of the    device under test by means of the directional element,-   forwarding the reflected electromagnetic wave to a test and    measurement instrument via the directional element, wherein the test    and measurement instrument has a defined phase relation with the    signal generator,-   processing a reference signal by means of the test and measurement    instrument, wherein the reference signal is associated with the    wideband modulated signal, and-   determining a channel response by taking the reference signal and at    least one scattering parameter of the device under test into    account, which is determined by the test and measurement instrument,    wherein the scattering parameter depends on the reflected    electromagnetic wave.

Furthermore, embodiments of the present disclosure provide a test systemfor testing a device under test. The test system comprises at least onesignal generator configured to generate a wideband modulated signal. Thetest system comprises at least one test and measurement instrumenthaving a defined phase relation with the signal generator. Moreover, thetest system comprises at least one directional element configured toseparate incident electromagnetic waves and reflected electromagneticwaves. The directional element has at least a first port, a second portand a third port. The signal generator is connected with the directionalelement via the first port. The test and measurement instrument isconnected with the directional element via the second port. The thirdport is provided for connecting a device under test. The signalgenerator is configured to forward the wideband modulated signal to thedevice under test via the directional element. The directional elementis configured to separate an electromagnetic wave reflected at an inputof the device under test. The test and measurement instrument isconfigured to process a reference signal that is associated with thewideband modulated signal. The test and measurement instrument isconfigured to determine a channel response by taking the referencesignal and at least one scattering parameter of the device under testinto account, which is determined by the test and measurementinstrument, wherein the scattering parameter depends on the reflectedelectromagnetic wave.

Accordingly, a wideband modulated signal is used for determining atleast one scattering parameter of the device under test (port matchingmeasurement). In fact, a signal generator and a test and measurementinstrument are used together instead of a vector network analyzer formeasuring the port matching of the device under test. Therefore, thesame test system, particularly the same setup of the test system, can beused for measuring the port matching (parameters) as well as otherparameters that require a modulated stimulus, for instance parametersassociated with ACLR and/or EVM measurements.

Therefore, the signal generator may be established by a vector signalgenerator.

Generally, the wideband modulated signal provided by the signalgenerator does not only cover a given frequency range, but also acertain amplitude range. Therefore, the wideband modulated signalcombines a continuous wave frequency sweep and level sweep into a singlestimulus. Therefore, the entire testing time can be reducedappropriately, as the single stimulus is sufficient instead of using acontinuous wave frequency and level sweep.

The channel response may also be called channel frequency response,frequency response or rather transfer function. In general, the channelresponse is associated with the signal generator and the device undertest. In fact, the channel response corresponds to a quantitativemeasure of the output spectrum of a system in response to a stimulus.Therefore, the channel response is used to characterize dynamics of thesystem. The respective system comprises the signal generator and thedevice under test. The scattering parameters of the device under testinfluence the channel response and, therefore, they are taken intoconsideration when determining the channel response.

The directional element is generally configured to separate incidentelectromagnetic waves, namely the wideband modulated signal or ratherthe single stimulus of the signal generator, and reflectedelectromagnetic waves, namely the ones reflected at the input of thedevice under test.

For instance, the directional element is established by means of thedirectional coupler, particularly a 3-port directional coupler or a4-port directional coupler.

Further, the signal generator, namely the respective signal sourceproviding the stimulus, as well as the test and measurement instrument,namely the signal receiver, are capable of transmitting/receivingwideband modulated (arbitrary) signals rather than continuous wavesignals.

In general, the test system, particularly the respective test setup ofthe test system, is enabled to allow typical and known vector networkanalyzer calibration routines and standards.

Furthermore, the present disclosure allows smaller and morecost-effective test systems or rather test setups.

According to an aspect, the reflected electromagnetic wave is associatedwith the wideband modulated signal forwarded to the device under test.The respective reflected electromagnetic wave forwarded to the deviceunder test is reflected partly at the input of the device under test dueto an impedance mismatch.

Another aspect provides that the channel response is associated with achannel established between the signal generator and the device undertest. In other words, the channel response, also called transferfunction, would correspond to the (inherent) forward transmission of thedevice under test in case of a matched device under test.

A further aspect provides that the at least one scattering parameteralso depends on an incident electromagnetic wave associated with thewideband modulated signal. Accordingly, the at least one scatteringparameter used for determining the channel response depends on theincident electromagnetic wave, namely the one associated with thewideband modulated signal generated, as well as the reflectedelectromagnetic wave. Thus, the at least one scattering parametercorresponds to the S11 parameter associated with the input reflectioncoefficient. The S11 parameter is obtained by dividing the reflectedelectromagnetic wave by the incident electromagnetic wave. This can bedone by means of the test and measurement instrument, which receives thereflected electromagnetic wave via the directional element as well asthe reference signal that is associated with the wideband modulatedsignal generated by the signal generator.

According to another aspect, the test and measurement instrumentreceives a transmitted signal from an output of the device under test.The transmitted signal, namely the one that is processed by the deviceunder test, is measured by means of the test and measurement instrument.Hence, the test and measurement instrument is connected with the outputof the device under test for receiving the transmitted signal. Thetransmitted signal is used to determine the S21 parameter that isassigned to the forward transmission of the device under test.

In general, the transmitted signal is associated with the widebandmodulated signal that has been forwarded to the input of the deviceunder test.

Particularly, the channel response is determined by taking the referencesignal, a S11 parameter of the device under test and a S21 parameter ofthe device under test, into account. The respective scatteringparameters, namely the S11 parameter and the S21 parameter, aredetermined by the test and measurement instrument based on the receivedsignals or rather electromagnetic waves, namely the reference signal,the reflected electromagnetic wave received from the directional elementas well as the transmitted signal received from the output of the deviceunder test.

According to another aspect, a modulation accuracy and/or a non-lineareffect are/is determined simultaneously. The modulated accuracy may bedetermined by means of the EVM or ACLR measurement(s). The non-lineareffect may correspond to a compression. In fact, the above-mentionedinformation may be obtained simultaneously when obtaining the at leastone scattering parameter. Therefore, the entire testing time requiredcan be reduced further.

Furthermore, hot S-parameter measurements may be performed. This meansthat the device under test is tested under real-world conditions.Therefore, signals typically used when the device under test is operatedare used for the testing purposes. In other words, the idea of hotS-parameter measurements is to put the device under test under realisticoperating conditions by applying the appropriate large-signal stimulussignal, namely the wideband modulated signal provided by the signalgenerator.

According to another aspect, a second directional element is connectedwith an output of the device under test. Therefore, a S22 parameter ofthe device under test can be determined by means of the test system. TheS22 parameter corresponds to the output reflection coefficient.

In fact, the S22 parameter may be determined in a similar manner as theS11 parameter is determined as mentioned above. However, the respectivesignal, namely the wideband modulated signal provided by the signalgenerator, is forwarded to the output of the device under test insteadof its input such that an electromagnetic wave reflected at the outputof the device under test is forwarded to the test and measurementinstrument via the directional element.

Moreover, the reverse transmission, namely the S12 parameter, may alsobe determined in a similar manner as described above with regard to theS21 parameter.

According to an aspect, different S-parameters of the device under testare measured subsequently. Hence, a single port of the test andmeasurement instrument is connected with different components of thetest system and/or ports of the device under test in a subsequentmanner.

According to another aspect, different S-parameters of the device undertest are measured simultaneously while mapping respectiveelectromagnetic waves to different ports of the test and measurementinstrument. Hence, the test and measurement instrument has several portsthat are connected with different components of the test system and/ordifferent ports of the device under test simultaneously. Hence, the testand measurement instrument is configured to receive the respectiveelectromagnetic waves that are used to determine the differentS-parameters of the device under test.

A system error correction may be used to define a reference plane andcompensate for at least one non-ideal component within the test system.The test system may be configured to use system error correction todefine a reference plane and to compensate for at least one non-idealcomponent within the test system. Accordingly, a mismatch correction isprovided that generally improves the measurement of the parameters thatrequired a modulated stimulus.

The test and measurement instrument may receive the reference signal viaa data input and/or a radio frequency input connected with the signalgenerator. Therefore, a data associated with the wideband modulatedsignal may be provided and/or loaded via the data input, wherein thedata is processed by the test and measurement instrument in order togenerate the reference signal based on the data. The data input mayrelate to an interface for receiving a data storage medium.Alternatively, the data input is a data interface that is connected to acorresponding data interface of the signal generator.

Alternatively, a radio frequency connection may be established betweenthe test and measurement instrument and the signal generator such thatthe wideband modulated signal is directly forwarded to the test andmeasurement instrument.

The test and measurement instrument may obtain respective informationwith regard to the incident wave by means of the reference signal inorder to determine the S11 parameter.

Generally, S-parameters of the device under test, a modulation accuracyand a non-linear effect are determined with the same setup of the testsystem. In other words, the test system may be configured to performS-parameter measurements, modulation accuracy measurements andnon-linear effects measurements on the same setup. Accordingly,different kinds of measurements can be performed simultaneously in orderto determine the different measurement parameters mentioned above. Infact, the respective measurements may be done simultaneously by usingthe single wideband measurement signal rather than a continuous wavesweep. In other words, the same single stimulus can be used for alldifferent kinds of measurements.

An aspect provide that the test system comprises a test deviceconfigured to test the device under test. The test device has a housingthat encompasses the signal generator, the test and measurementinstrument and the directional element. Accordingly, a single device isused for testing the device under test. The directional element is aninternal directional element.

Alternatively, the respective components of the test system are formedseparately with respect to each other, wherein respective cables orrather connection lines are provided for interconnecting thesecomponents.

Moreover, a significant speed advantage is provided by the presentdisclosure. Since the same stimulus can be used for all measurements,additional time saving is possible.

Furthermore, several signal generators and/or several test andmeasurement instruments may be used that have a defined (known) phaserelation. Alternatively, a reference receiver may be used to ensure thedefined phase relation.

In addition, the device under test may correspond to a 1-port deviceunder test. Generally, the present disclosure is scalable from 1- toN-port devices under test. However, the number of signal generatorsand/or test and measurement instruments does not necessarily scale withthe number of ports of the device under test.

The present disclosure also ensures load-pull and/or source-pull.Load-pull corresponds to the process of systematically varying the loadimpedance presented to the device under test and monitoring a single orset of performance parameters. Source-pull corresponds to the process ofsystematically varying the source impedance presented to the deviceunder test and monitoring a single or set of performance parameters.

Generally, the test and measurement instrument may be established by avector signal analyzer or an oscilloscope. For instance, a digitaloscilloscope or rather an oscilloscope with I/Q interface is providedthat corresponds to the test and measurement instrument. Theoscilloscope may have an I/Q output interface, as the oscilloscopecomprises a processing module that is configured to process modulatedsignals to I/Q data, namely converting the modulated signals receivedinto I/Q data. The I/Q data obtained by means of the conversion may beoutputted via the I/Q output interface.

In fact, a vector signal analyzer and an oscilloscope can generally beused for the same purpose, namely a vector signal analysis. Therefore,the oscilloscope corresponds to the vector signal analyzer concerningthis functionality.

In any case, the signal generator is configured to generate a widebandsignal.

The test and measurement instrument, e.g. the oscilloscope or the vectorsignal analyzer, is configured to perform the vector signal analysis onthe signal received, e.g. measuring magnitude and phase of an inputsignal at a single frequency within the IF bandwidth of the instrument.Accordingly, the test and measurement instrument may be used to makein-channel measurements, such as error vector magnitude, code domainpower, and spectral flatness, on known signals.

As mentioned above, the oscilloscope may have a certain processingmodule that establishes the vector signal analysis functionality.

Therein and in the following, the term “module” is understood todescribe suitable hardware, suitable software, or a combination ofhardware and software that is configured to have a certainfunctionality.

The hardware may, inter alia, comprise a CPU, a GPU, an FPGA, an ASIC,or other types of electronic circuitry.

DESCRIPTION OF THE DRAWINGS

The foregoing aspects and many of the attendant advantages of theclaimed subject matter will become more readily appreciated as the samebecome better understood by reference to the following detaileddescription, when taken in conjunction with the accompanying drawings,wherein:

FIG. 1 schematically shows a representative embodiment of a test systemaccording to the present disclosure; and

FIG. 2 shows a flow-chart illustrating a representative method oftesting a device under test according to the present disclosure.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appendeddrawings, where like numerals reference like elements, is intended as adescription of various embodiments of the disclosed subject matter andis not intended to represent the only embodiments. Each embodimentdescribed in this disclosure is provided merely as an example orillustration and should not be construed as preferred or advantageousover other embodiments. The illustrative examples provided herein arenot intended to be exhaustive or to limit the claimed subject matter tothe precise forms disclosed. The illustrative examples provided hereinare not intended to be exhaustive or to limit the claimed subject matterto the precise forms disclosed. For the purposes of the presentdisclosure, the phrase “at least one of A, B, and C”, for example, means(A), (B), (C), (A and B), (A and C), (B and C), or (A, B, and C),including all further possible permutations when greater than threeelements are listed. In other words, the term “at least one of A and B”generally means “A and/or B”, namely “A” alone, “B” alone or “A and B”.

In FIG. 1 , a test system 10 is shown that is used to test a deviceunder test 12.

The test system 10 comprises at least one signal generator 14,particularly at least one vector signal generator, that is configured togenerate a wideband modulated signal that encompasses a certainfrequency range as well as a certain amplitude range.

The signal generator 14 is connected with a directional element 16,particularly a first port 18 of the directional element 16.

The directional element 16 also has a second port 20 that is assigned tothe device under test 12 such that a signal generated by the signalgenerator 14 can be forwarded to an input 22 of the device under test 12via the directional element 16, particularly the first port 18 as wellas the second port 20 of the directional element 16.

Furthermore, the test system 10 has a test and measurement instrument 24that is connected with a third port 26 of the directional element 16.The test and measurement instrument 24 may be established by a vectorsignal analyzer or rather an oscilloscope, namely an oscilloscope havingvector signal analysis functionality.

The directional element 16 may be assigned to a matched termination 28via its fourth port 29, which ensures that port matching measurements ofthe device under test 12 can be performed by the respective setup of thetest system 10 in an appropriate manner. Alternatively, the matchedtermination 28 may be integrated.

The test system 10 may also comprise a second directional element 30that is connected to an output 32 of the device under test 12, whereinthe second directional element 30 is optional or rather only used incertain measurements, as will be described later.

Generally, the test and measurement instrument 24 may also be assignedto the output 32 of the device under test 12 in order to receive atransmitted signal provided at the output 32 of the device under test12, as will be described later.

The test and measurement instrument 24 may comprise a data input 34 viawhich a data, for instance a data file, may be inputted, which isprocessed by the test and measurement instrument 24. The data is used toobtain a reference signal associated with the wideband modulated signalgenerated by the signal generator 14.

The data input 34 can be configured to receive a data storage mediumthat comprises information with regard to the wideband modulated signalgenerated. The data input 34 may also be established by an interface viawhich the test and measurement instrument 24 has a data connection tothe signal generator 14 for receiving data from the signal generator 14,which relates to the wideband modulated signal generated.

The test and measurement instrument 24 may also comprise a radiofrequency input 36 that is connected to the signal generator 14 via arespective radio frequency line 38. Thus, the test and measurementinstrument 24 receives a radio frequency signal originating from thesignal generator 14, which is associated with the wideband modulatedsignal generated.

In any case, the test and measurement instrument 24 receives the data orrather the radio frequency signal such that the reference signal isobtained by the test and measurement instrument 24, wherein thereference signal is associated with the wideband modulated signalgenerated by the signal generator 14.

In general, the test system 10 is enabled to determine scatteringparameters (S-parameters) of the device under test 12, a modulationaccuracy and at least one non-linear effect with the same setup of thetest system 10. This means that it is not necessary to establish twodifferent test stations or rather different test setups in order todetermine the above-mentioned parameters.

This will be described hereinafter in more detail with reference to FIG.2 illustrating a flow-chart of a method for testing the device undertest 12 by using the test system 10 as illustrated in FIG. 1 .

In a first step S1, a wideband modulated signal is generated by thesignal generator 14.

In a second step S2, the wideband modulated signal is forwarded from thesignal generator 14 to the input 22 of the device under test 12 via thedirectional element 16. The directional element 16 is generallyconfigured to separate an incident electromagnetic wave and a reflectedelectromagnetic wave.

In a third step S3, an electromagnetic wave reflected at the input 22 ofthe device under test 12 is separated by means of the directionalelement 16, which is reflected due to an impedance mismatch of the input22 with respect to the test system 10.

In a fourth step S4, the reflected electromagnetic wave is forwarded tothe test and measurement instrument 24 via the directional element 16,namely the third port 26 of the directional element 16, to which thetest and measurement instrument 24 is connected.

In a fifth step S5, a reference signal associated with the widebandmodulated signal generated by the signal generator 14 is processed bythe test and measurement instrument 24. The reference signal may beobtained via the data input 34 or rather the radio frequency input 36that is connected with the signal generator 14.

In a sixth step S6, at least one scattering parameter of the deviceunder test 12 is determined by means of the test and measurementinstrument 24. For instance, the test and measurement instrument 24determines the S11 parameter that depends on the reflectedelectromagnetic wave obtained from the directional element 16,particularly its third port 26, as well as an incident electromagneticwave. The incident wave may be obtained from the reference signal. TheS11 parameter is obtained by dividing the reflected electromagnetic waveby the incident electromagnetic wave.

Accordingly, the at least one scattering parameter depends on thereflected electromagnetic wave as well as the incident electromagneticwave that is associated with the wideband modulated signal generated bymeans of the signal generator 14.

In a seventh step S7, a transmitted signal is received by the test andmeasurement instrument 24, which was outputted by the device under test12 based on the wideband modulated signal forwarded to the device undertest 12. In other words, the transmitted signal is received from theoutput 32 of the device under test 12.

In an eighth step S8, a channel response is determined by taking thereference signal and the at least one scattering parameter of the deviceunder test 12 into account. The channel response is determined by thetest and measurement instrument 24. The channel response is also knownas channel frequency response, frequency response or rather transferfunction. In fact, the channel response is associated with the channelestablished between the signal generator 14 and the device under test12.

In fact, the channel response is determined by taking the S11 parameteras well as the S21 parameter of the device under test 12 into account,wherein the latter one is derived from the transmitted signal.

Therefore, the test and measurement instrument 24 is configured todetermine the S21 parameter of the device under test 12.

Moreover, further scattering parameters of the device under test 12 canbe determined by using the signal generator 14 as well as the test andmeasurement instrument 24.

For instance, the S22 parameter is determined by using the seconddirectional element 30 that is connected to the output 32 of the deviceunder test 12. The signal generator 14 also generates the widebandmodulated signal that is forwarded to the output 32 of the device undertest 12, wherein the second directional element 30 separates anelectromagnetic wave reflected at the output 32 of the device under test12. Hence, the test and measurement instrument 24 takes the referencesignal as well as the electromagnetic wave reflected at the output 32 ofthe device under test 12 into account to determine the S22 parameter.

Moreover, the S12 parameter may also be determined in a similar manneras described above.

Besides the scattering parameters, the same setup of the test system 10can be used to simultaneously measure a modulation accuracy as well asnon-linear effects. The modulation accuracy can be determined by anerror vector magnitude (EVM) measurement and/or an adjacent channelleakage power ratio (ACLR) measurement. The at least one non-lineareffect may relate to a compression.

The respective measurements can be done simultaneously, as the widebandmodulated signal is used for performing the respective measurements. Thewideband modulated signal encompasses a certain frequency range as wellas a certain amplitude range, which correspond to a continuous wavefrequency and level sweep.

Therefore, the time required for the measurements can be reducedsignificantly. In other words, a significant speed advantage inmeasuring the respective scattering parameters is obtained, as thescattering parameters are measured by means of the wideband modulatedsignal instead of a continuous wave frequency and level sweep.

In addition, the entire measurement time for determining the respectiveparameters can be reduced further, as the same single stimulus, namelythe wideband modulated signal, can be used for all different kinds ofmeasurements mentioned above.

In fact, the S-parameter measurements can be performed by means of hotS-parameter measurements, wherein real operation signals are generatedand forwarded to the device under test 12.

In addition, a system error correction may be used to define a referenceplane and compensate for at least one non-idle component within the testsystem 10 such that the respective measurements can be performed in amore accurate manner, particularly the error vector magnitude (EVM)measurement and/or the adjacent channel leakage power ratio (ACLR)measurement.

The different S-parameters of the device under test 12 can be measuredsubsequently while connecting a respective port of the test andmeasurement instrument 24 with a respective component of the test system10 and/or port of the device under test 12 in a subsequent manner.

Alternatively, the different S-parameters of the device under test 12can be measured simultaneously while mapping respective electromagneticwaves to different ports of the test and measurement instrument 24simultaneously. Furthermore, several ports of the test and measurementinstrument 24 are occupied in the respective test setup of the testsystem 10.

In general, the S-parameters of the device under test 12, a modulationaccuracy and a non-linear effect can be determined with the same setupof the test system 10 simultaneously. The same stimulus, namely thewideband modulated signal generated by the signal generator 14, can beused to determine the respective different kinds of parameters.

Accordingly, costs and time can be reduced, as a single test setup issufficient to obtain and measure the respective parameters rather thantwo different test stations or rather test setups.

The signal generator 14, the directional element 16 as well as the testand measurement instrument 24 may be encompassed in a single testingdevice 40 that has a common housing 42 illustrated by dashed lines inFIG. 1 .

The housing 42 encompasses the respective components of the test system10, namely the signal generator 14, the directional element 16 as wellas the test and measurement instrument 24.

In general, time and cost savings can be obtained by using the widebandmodulated signal as the single stimulus rather than a continuous wavesweep, which is done by means of a vector network analyzer. In addition,the costs for testing can be reduced further, as it is not necessary topurchase a relatively expensive vector network analyzer.

Certain embodiments disclosed herein, particularly the respectivemodule(s), utilize circuitry (e.g., one or more circuits) in order toimplement standards, protocols, methodologies or technologies disclosedherein, operably couple two or more components, generate information,process information, analyze information, generate signals,encode/decode signals, convert signals, transmit and/or receive signals,control other devices, etc. Circuitry of any type can be used.

In an embodiment, circuitry includes, among other things, one or morecomputing devices such as a processor (e.g., a microprocessor), acentral processing unit (CPU), a digital signal processor (DSP), anapplication-specific integrated circuit (ASIC), a field-programmablegate array (FPGA), a system on a chip (SoC), or the like, or anycombinations thereof, and can include discrete digital or analog circuitelements or electronics, or combinations thereof. In an embodiment,circuitry includes hardware circuit implementations (e.g.,implementations in analog circuitry, implementations in digitalcircuitry, and the like, and combinations thereof).

In an embodiment, circuitry includes combinations of circuits andcomputer program products having software or firmware instructionsstored on one or more computer readable memories that work together tocause a device to perform one or more protocols, methodologies ortechnologies described herein. In an embodiment, circuitry includescircuits, such as, for example, microprocessors or portions ofmicroprocessor, that require software, firmware, and the like foroperation. In an embodiment, circuitry includes one or more processorsor portions thereof and accompanying software, firmware, hardware, andthe like.

The present application may reference quantities and numbers. Unlessspecifically stated, such quantities and numbers are not to beconsidered restrictive, but exemplary of the possible quantities ornumbers associated with the present application. Also in this regard,the present application may use the term “plurality” to reference aquantity or number. In this regard, the term “plurality” is meant to beany number that is more than one, for example, two, three, four, five,etc. The terms “about”, “approximately”, “near” etc., mean plus or minus5% of the stated value.

1. A method for testing a device under test by using a test system, saidmethod comprising the steps of: generating a wideband modulated signalby at least one signal generator, forwarding said wideband modulatedsignal to an input of a device under test via at least one directionalelement, separating an electromagnetic wave reflected at said input ofsaid device under test by said directional element, forwarding saidreflected electromagnetic wave to a test and measurement instrument viasaid directional element, said test and measurement instrument having adefined phase relation with said signal generator, processing areference signal by said test and measurement instrument, wherein saidreference signal is associated with said wideband modulated signal, anddetermining a channel response by taking said reference signal and atleast one scattering parameter of said device under test into account,which is determined by said test and measurement instrument, whereinsaid scattering parameter depends on said reflected electromagneticwave.
 2. The method according to claim 1, wherein said reflectedelectromagnetic wave is associated with said wideband modulated signalforwarded to said device under test.
 3. The method according to claim 1,wherein said channel response is associated with a channel establishedbetween said signal generator and said device under test.
 4. The methodaccording to claim 1, wherein said at least one scattering parameteralso depends on an incident electromagnetic wave associated with saidwideband modulated signal.
 5. The method according to claim 1, whereinsaid signal analyzer receives a transmitted signal from an output ofsaid device under test.
 6. The method according to claim 1, wherein saidchannel response is determined by taking said reference signal, a S11parameter of said device under test and a S21 parameter of said deviceunder test into account.
 7. The method according to claim 1, wherein atleast one of a modulation accuracy and a non-linear effect is determinedsimultaneously.
 8. The method according to claim 1, wherein hotS-parameter measurements are performed.
 9. The method according to claim1, wherein a second directional element is connected with an output ofsaid device under test, and wherein a S22 parameter of said device undertest is determined by said signal generator and said test andmeasurement instrument.
 10. The method according to claim 1, whereindifferent S-parameters of said device under test are measuredsubsequently.
 11. The method according to claim 1, wherein differentS-parameters of said device under test are measured simultaneously whilemapping respective electromagnetic waves to different ports of said testand measurement instrument.
 12. The method according to claim 1, whereina system error correction is used to define a reference plane and tocompensate for at least one non-ideal component within said test system.13. The method according to claim 1, wherein said test and measurementinstrument receives said reference signal via at least one of a datainput and a radio frequency input connected with said signal generator.14. The method according to claim 1, wherein S-parameters of said deviceunder test, a modulation accuracy and a non-linear effect are determinedwith the same setup of said test system.
 15. A test system for testing adevice under test, said test system comprising: at least one signalgenerator configured to generate a wideband modulated signal, at leastone test and measurement instrument having a defined phase relation withsaid signal generator, and at least one directional element configuredto separate incident electromagnetic waves and reflected electromagneticwaves, wherein said directional element has at least a first port, asecond port and a third port, said signal generator being connected withsaid directional element via said first port, said test and measurementinstrument being connected with said directional element via said secondport, and said third port being provided for connecting a device undertest, wherein said signal generator is configured to forward saidwideband modulated signal to said device under test via said directionalelement, wherein said directional element is configured to separate anelectromagnetic wave reflected at an input of said device under test,wherein said test and measurement instrument is configured to process areference signal that is associated with said wideband modulated signal,and wherein said test and measurement instrument is configured todetermine a channel response by taking said reference signal and atleast one scattering parameter of said device under test into account,which is determined by said test and measurement instrument, whereinsaid scattering parameter depends on said reflected electromagneticwave.
 16. The test system according to claim 15, wherein saiddirectional element is established by a directional coupler.
 17. Thetest system according to claim 15, wherein said test system comprises atest device configured to test said device under test, said test devicehaving a housing that encompasses said signal generator, said test andmeasurement instrument and said directional element.
 18. The test systemaccording to claim 15, wherein said test system is configured to performS-parameter measurements, modulation accuracy measurements andnon-linear effects measurements on the same setup.
 19. The test systemaccording to claim 15, wherein said test system is configured to usesystem error correction to define a reference plane and to compensatefor at least one non-ideal component within said test system.
 20. Thetest system according to claim 15, wherein said test and measurementinstrument is a vector signal analyzer or an oscilloscope.